• Journal of Positioning, Navigation, and Timing
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• 제4권4호
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• pp.205-211
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• 2015

The Global Navigation Satellite System (GNSS) is undergoing dramatic changes. Nowadays, much more satellites are transmitting navigation data at more frequencies. A multi-GNSS analysis is performed to improve the positioning accuracy by processing combined observations from different GNSS. The multi-GNSS technique can improve significantly the positioning accuracy. In this paper, we present a combined Global Positioning System (GPS), the GLObal NAvigation Satellite System (GLONASS), the China Satellite Navigation System (BeiDou), and the Quasi-Zenith Satellite System (QZSS) standard point positioning (SPP) method to exploit all currently available GNSS observations at Mokpo (MKPO) station in South Korea. We also investigate the multi-GNSS data recorded at MKPO reference station. The positioning accuracy is compared with several combinations of the satellite systems. Because of the different frequencies and signal structure of the different GNSS, intersystem biases (ISB) parameters for code observations have to be estimated together with receiver clocks in multi-GNSS SPP. We also present GPS/GLONASS and GPS/BeiDou ISB values estimated by the daily average.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.387-395
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• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

• Journal of Positioning, Navigation, and Timing
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• 제4권2호
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• pp.73-77
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• 2015

Global Positioning System (GPS) Precise Point Positioning (PPP) has been extensively used for geodetic applications. Since December 2012, BeiDou navigation satellite system has provided regional positioning, navigation and timing (PNT) services over the Asia-Pacific region. Recently, many studies on BeiDou system have been conducted, particularly in the area of precise orbit determination and precise positioning. In this paper PPP method based on BeiDou observations are presented. GPS and BeiDou data obtained from Mokpo (MKPO) station are processed using the Korea Astronomy and Space Science Institute Global Navigation Satellite System (GNSS) PPP software. The positions are derived from the GPS PPP, BeiDou B₁/B₂ PPP and BeiDou B₁/B₃ PPP, respectively. The position errors on BeiDou PPP show a mean bias < 2 cm in the east and north components and approximately 3 cm in the vertical component. It indicates that BeiDou PPP is ready for the precise positioning applications in the Asia-Pacific region. In addition, BeiDou tropospheric zenith total delay (ZTD) is compared to GPS ZTD at MKPO station. The mean value of their difference is approximately 0.52 cm.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.45-49
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• 2004

The Navstar Global Positioning System(GPS) is an advanced navigation satelite system for determination of position, velocity and time. It can provide three-dimensional positioning on a global basis, independent of weather, 24 hours per day. Test results show that the carrier phase and pseudorange corrections are suitable for a kinematic GPS system. Using these corrections are more effective than using raw GPS data, since fewer bits are required for transmission Additionally, the number of computation required at the rover is reduced when corrections, rather than raw measurement are transmitted

• 한국농공학회지
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• 제42권
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• pp.9-16
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• 2000

GPS(Global Positioning System) surveying is an effective method using satellite measurement system and can be applied to construction of digital map of irrigation canal networks. In this study, GPS surveying method for irrigation structures was developed. A selected main canal of an irrigation district were surveyed by GPS. The obtained surveying results were corrected by post-processed DGPS (Differential Global Positioning System) and imported to GIS for the digital map construction.

• Journal of Positioning, Navigation, and Timing
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• 제8권2호
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• pp.87-94
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• 2019

The Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) positioning has been widely used in geodesy, surveying, and navigation fields. RTK can benefit enormously from the integration of multi-GNSS. In this study, we develop a GPS/BeiDou Navigation Satellite System (BDS) RTK integration algorithm for long baselines ranging from 128 km to 335 km in South Korea. The positioning performance with GPS/BDS RTK, GPS-only RTK, and BDS-only RTK is compared in terms of the positioning accuracy. An improvement of positioning accuracy over long baselines can be found with GPS/BDS RTK compared with that of GPS-only RTK and that of BDS-only RTK. The positioning accuracy of GPS/BDS RTK is better than 2 cm in the horizontal direction and better than 5 cm in the vertical direction. A lower Relative Dilution of Precision (RDOP) value with GPS/BDS integration can obtain a better positional precision for long baseline RTK positioning.

• 대한공간정보학회지
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• 제10권1호
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• pp.51-57
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• 2002

GPS(Global Positioning System)가 토목공사, 기준점 측량, 구조물 변형등 측지 및 측량분야에 활용성이 우수하다는 것은 여러 연구 결과에서 입증되었지만, 고층 빌딩이 산재한 도심지나 공장지역등 GPS 위성신호의 수신이 최소 4개 이하로 떨어지는 장소에서서의 GPS 정적 위치결정 정확도는 현저히 떨어진다는 것을 알 수 있다. 따라서 GPS 위성과 GLONASS(GLObal Navigation Satellite System)를 결합하여 위성의 가시성을 높여 보다 많은 위치 정보를 획득하여 향상된 정적 위치결정 정확도를 얻으려 한다. 그 결과 GPS/GLONASS 결합시스템으로 도심지에서 다중경로, 신호의 고도각, 가시위성 부족에 의한 위치 결정정확도를 저하하는 것을 향상시켰다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.165-169
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• 2008

In other side the recent construction industry is a skyscraper, a large scale and a sophistication, a construct site have many problems that an aging of worker and shortage of work force. The purpose of this study was to develop the location of tower crane and the simulation technology of tover crane. The automation of tower carne is a important component in skyscrapers. Specially, this study suggested that it was to develop the exact location system through GPS(Global Positioning System) better than former times.

• 한국전자파학회논문지
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• 제22권2호
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• pp.208-213
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• 2011

본 논문은 안전 서비스를 제공하는 Global Positioning System(GPS) 보호 비(Ratio of Interference to Noise: I/N) 도출을 위해 Ultra Wide Band(UWB)로부터 GPS 간섭 영향을 분석하였다. GPS 측위 오차 2.5 m 이하를 만족하기 위한 UWB 송신기와 GPS 수신기 사이의 최소 보호 거리를 산출하였고, 최소 결합 손실 방법(Minimum Coupling Loss: MCL)을 이용하여 측위 오차를 만족하는 UWB 송신기와 GPS 수신기 사이의 보호 거리 값에 근거하여 GPS 시스템의 보호비(I/N)를 도출하였다. 그 결과, 측위 오차 2.5 m 이하를 만족하기 위한 GPS 보호 거리는 10 m 이상으로 계산되었고, 이를 만족하기 위한 GPS 보호비(I/N)는 -20 dB 이하로 도출되었다. 제안된 GPS 시스템 보호비는 국제전기통신연합(ITU-R)에서 제안한 GPS 시스템 중 안전 서비스에 해당하는 보호비(I/N)를 만족시킴을 확인하였다. 또한, 본 논문을 통해 얻어진 GPS 보호 비의 결과는 안정적인 국내 GPS 시스템 운용을 위한 기준으로 이용될 수 있다.

• 정보통신설비학회논문지
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• 제9권3호
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• pp.92-101
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• 2010

Energy efficiency and safe mobility are the two key constituents of the future automobile. The technologies that enable these features are now heavily dependent upon information and communication technology rather than traditional auto-mechanical technology. This paper presents an exploratory project 'Smart&Green Vehicle Project' at Western Michigan University which is to improve the geographical location accuracy of vehicles and to study various applications of making such location data available. Global Positioning System (GPS), Inertial Navigation System (INS), Vehicular Ad-hoc Network (VANET) technology, and data fusion among these technologies are investigated. Testing and evaluation is done on systems which will gather vehicular positioning data during GPS signal loss. Vehicles in urban settings do not acquire accurate positioning data from GPS alone; therefore there is a need for exploration into technology that can assist GPS in urban settings. The goal of this project is to improve the accuracy of positioning data during a loss of GPS signal. Controlled experiments are performed to gather data which aided in assessing the feasibility of these technologies for use in vehicular platforms.